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Characterization and supercritical carbon dioxide extraction of walnut oil
Author(s) -
Oliveira Rui,
Fátima Rodrigues M.,
Gabriela BernardoGil M.
Publication year - 2002
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-002-0465-y
Subject(s) - linoleic acid , chemistry , supercritical fluid , chromatography , hexane , extraction (chemistry) , supercritical carbon dioxide , juglans , supercritical fluid extraction , food science , fatty acid , biochemistry , organic chemistry
Walnut ( Juglans regia L.) oil was extracted with compressed carbon dioxide (CO 2 ) in the temperature range of 308 to 321 K and in the pressure range of 18 to 23.4 MPa. The influence of particle size was also studied at a superficial velocity of 0.068 cm/s, within a tubular extractor of 0.2 L capacity (cross‐sectional area of 16.4 cm 2 ). FFA, sterol, TAG, and tocopherol compositions were not different from those of oil obtained with n ‐hexane. The main FA was linoleic acid (56.5%), followed by oleic acid (21.2%) and linolenic acid (13.2%). The main TAG was LLL (linoleic, linoleic, linoleic) (24.4%), followed by OLL (oleic, linoleic, linoleic) (19.6%) and LLLn (linoleic, linoleic, linolenic) (18.4%). The main component of sterols was β‐sitosterol (85.16%), followed by campesterol (5.06%). The amount of cholesterol was low (0.31 and 0.16% for oils extracted by n ‐hexane and supercritical fluid extraction, respectively. The CO 2 ‐extracted oil presented a larger amount of tocopherols (405.7 μg/g oil) when compared with 303.2 μg/g oil obtained with n ‐hexane. Oxidative stability determined by PV and the Rancimat method revealed that walnut oil was readily oxidized. Oil extracted by supercritical CO 2 was clearer than that extracted by n ‐hexane, showing some refining. A central composite, nonfactorial design was used to optimize the extraction conditions using the software Statistica , Version 5. The best results were found at 22 MPa, 308 K, and particle diameter (Dp) −0.1 mm.